Blindstitch sewing machine

ABSTRACT

A BLINDSTITCH SEWING MACHINE HAVING A WORK SUPPORTING MEMBER WHICH IS RETAINED IN A FIXED POSITION DURING OPERATION OF THE MACHINE. THE MACHINE IS PROVIDED WITH A PAIR OF NODE FORMING ELEMENTS ARRANGED SIDE BY SIDE IN THE WORK SUPPORTING MEMBER OF THE MACHINE. THESE NODEFORMING ELEMENTS ARE SIMPLY RECIPROCATED TOWARD AND AWAY FROM THE WORK AND ARE ADAPTED TO PRODUCE NODES IN THE WORK BEING STITCHED AT SLIGHTLY DIFFERENT REGIONS OF THE STITCH FORMING ZONE OF THE MACHINE. THE NODE-FORMING ELEMENTS AR SHIFTED IN OPPOSITE DIRECTIONS IN RELATION TO EACH OTHER, SO THAT AT ONE TIME ONE NODE-FORMING ELEMENT WILL BE ACTIVE WHILE AT ANOTHER TIME THE OTHER NODE-FORMING ELEMENT WILL BE ACTIVE. FOR OPERATING THE NODE-FORMING ELEMENTS BY THE MAIN DRIVE SHAFT OF THE MACHINE A ROTARY ECCENTRIC MEMBER IS PROVIDED WHICH IS DRIVEN AT HALF THE ANGULAR SPEED OF THE MAIN DRIVE SHAFT. THIS PERMITS THE SHIFTING OF ONE NODE FORMER INTO ACTIVE POSITION AND THE OTHER NODE FORMER OUT OF ACTIVE POSITION DURING ONE CYCLE OF OPERATION OF THE MACHINE, WHEREAS THE REVERSE SITUATION TAKES PLACE ON THE NEXT CYCLE OF OPERATION OF THE MACHINE. NO MOVEMENT IS IMPARTED TO THE NODE FORMING ELEMENTS IN OR OPPOSITE TO THE DIRECTION OF MOVEMENT OF THE WORK BEING STITCHED, THE ONLY MOVEMENT OF EACH NODE-FORMING ELEMENT BEING PERPENDICULAR TO THE PATH OF MOVEMENT OF THE WORK IN THE STITCH FORMING ZONE. FEED ROLLERS ARE MOUNTED ON THE WORK SUPPORTING MEMBER OF THE MACHINE, WITH THEIR AXES PERPENDICULAR TO THE LINE OF STITCH FORMATION. THESE FEED ROLLERS SERVE TO URGE THE WORK UPWARDLY IN TWO DIFFERENT BUT ADJACENT REGIONS TOWARD A FIXED PRESSER FOOT.

R. w. FLETCHER ET AL 3,572,269

BLINDSTITCH SEWING MACHINE March 23', 1971 8 Sheets-Sheet 1 Filed Dec. 5, 1969 March 23, 1971 R. w. FLETCHER ETAL 3,572,269

' BLINDSTITCH SEWING MACHINE 8 Sheets-Sheet 2 Filed Dec. 3, 1969 I Filed Dec. 3, 1969 March 23, 1971 w. FLETCHER ET AL 3,572,269

BLINDSTITCH SEWING MACHINE 8 Sheets-Sheet 5 March 23, 1971 w E R ET AL 3,572,269

BLINDSTITCH SEWING MACHINE Filed Dec. 3, 1969 8 Sheets-Sheet 4 R. w. FLETCHER ET AL 3,572,269

BLINDSTITCH SEWING MACHINE 7 March 23, 1971 8 Sheets-Sheet 5 Filed Dec IS, 1969 March 23, 1971 Filed Dec. 3, 1969 R. W. FLETCHER ET AL BLINDSTITCH SEWING MACHINE 8 Sheets-Sheet 6 R. w. FLETCHER ET AL 3,572,269

BLINDS'IITCH SEWING MACHINE March 23, 1971 8 Sheets-Sheet 7 Filed Dec. 5, 1969 FIG.I3A. FIGIBB. FIG.|3C.

United States Patent 3,572,269 BLINDSTITCH SEWING MACHINE Roy W. Fletcher, Riverdale, and Anthony D. Forte, Chicago, Ill., assignors to Union Special Machine Company, Chicago, Ill.

Filed Dec. 3, 1969, Ser. No. 881,738 Int. Cl. D05b 1/24 US. Cl. 112178 15 Claims ABSTRACT OF THE DISCLOSURE A blindstitch sewing machine having a work supporting member which is retained in a fixed position during operation of the machine. The machine is provided with a pair of node'forming elements arranged side by side in the work supporting member of the machine. These nodeforming elements are simply reciprocated toward and away from the work and are adapted to produce nodes in the work being stitched at slightly different regions of the stitch forming zone of the machine. The node-forming elements are shifted in opposite directions in relation to each other, so that at one time one node-forming element will be active while at another time the other node-forming element will be active. For operating the node-forming elements by the main drive shaft of the machine a rotary eccentric member is provided which is driven at half the angular speed of the main drive shaft. This permits the shifting of one node former into active position and the other node former out of active position during one cycle of operation of the machine, whereas the reverse situation takes place on the next cycle of operation of the machine. No movement is imparted to the node forming elements in or opposite to the direction of movement of the work being stitched; the only movement of each node-forming element being perpendicular to the path of movement of the work in the stitch forming zone. Feed rollers are mounted on the work supporting member of the machine, with their axes perpendicular to the line of stitch formation. These feed rollers serve to urge the work upwardly in two different but adjacent regions toward a fixed presser foot.

The present invention relates to improvements in single needle, non-skip stitch, blind stitch sewing machines such as are used for the tacking of inside facings to the front or forepart of womens medium and light weight coats. The machine is adapted to apply stitches which catch alternately on the body and fold of the coat to hold the latter in shape. For this purpose the machine is provided with two independently yielding ridge forming members which lift portions of the work into the path of the curved needle, as the latter swings in a conventional manner, and thus causes the needle to penetrate the outer layer of fabric in the way desired.

It has been found that blindstitch machines, as heretofore constructed, are quite satisfactory in dealing with medium and light weight materials, but difiiculties have been encountered in the use of such previously known machines for the face tacking of heavy materials. Also, prior blindstitch machines used for the hemming of womens coats have been unable to cross heavy seams which may have a thickness of up to nine or sometimes even twelve plies of fabric. Heretofore n0 machine has been produced that is capable of producing the desired hemming of garments in which the hemming line of stitching must cross heavy seams provided between different sections of the garment. Attempts to perform such operations on machines as heretofore constructed have resulted in various difficulties, such as the skipping of stitches or the breaking of thread in the course of the stitching operation. Ac-

cordingly it has been found necessary in the past to provide such lines of stitching by hand rather than by a machine, or at least to use the machine only for applying stitches in regions between transversely extending seams and then skip over such seams and later complete the hemming operation by hand.

An important feature of the present invention, which adapts blindstitch sewing machines embodying the invention to perform the stitching operations mentioned without running into difficulties, is the provision of a special, novel type of node-forming mechanism for presenting the work into the path of the needle in the proper way. Toward the foregoing end, the machine of the present invention, is provided with a double plunger type of nodeforming mechanism. This mechanism is provided with two vertically disposed and shiftable node-forming plungers which are alternately put into and out of operative position.

A further aspect of the invention involves the special construction of the node-forming plungers and the means which presents them alternately into and out of engagement with the work in closely positioned regions, so as to insure the proper formation of the desired blindstitch. It has been found that this new node-forming or ridge-forming mechanism overcomes various objections encountered in the use of machines provided with previously known types of ridge forming elements. For example, it overcomes the tendency of conventional, oscillatory ridgeforming disks heretofore used on blindstitch sewing machines to slightly push the material backwardly against the direction of feed on the return stroke of the disks. This difiiculty is completely eliminated by the employment of ridge forming elements in the form of plungers which are only reciprocated in a direction perpendicular to the plane along which the work is being advanced in the course of stitching.

Another important feature of the invention is the offset construction of the two plunger members embodied therein. This enables the mounting of the plunger members in a desirable position, with provisions for imparting reciprocating movements thereto, while at the same time the active portions of these members, which serve to provide the desired ridges in the work being stitched, are disposed closely adjacent each other, with a slidable relation between adjacent vertical faces thereof.

Still another feature of the invention is the particular construction of the housings in which the plungers are mounted, these housings facilitating the proper operation of the plungers.

A different, and highly advantageous feature of the invention is the provision of rollers which are spring urged upwardly against the stationary presser foot, two such rollers being provided to cooperate with the work, at opposite sides of the line of stitching, in a region beyond but closely adjacent to the stitch forming zone.

With respect to the plungers, the present invention enables adjustment of each independently of the other, in relation to the work supporting surface and the stitch forming mechanism.

Other objects, features and advantages of the invention will appear from the detailed description of an illustrative embodiment of the invention which will now be given in relation to the accompanying drawings, in which:

FIG. 1 is a view showing partly in front elevation and partly in vertical section, a machine embodying the invention;

FIG. 2 is a vertical sectional view through the machine taken along the line 22 of FIG. 1;

FIG. 3 is a plan view of a part of the machine, showing the work supporting portion of the machine;

FIG. 4 is a view, partly in elevation as seen from the J left in FIG. 1 and partly in vertical section, illustrating only a portion of the machine;

FIG. 5 is a horizontal sectional view through a portion of the work support member of the machine, taken along the line 5-5 of FIG. 4;

FIG. 6 is a detail view in vertical section, taken along the line 66 of FIG. 7;

FIG. 7 is a detail view of a part of the work supporting portion of the machine, in elevation as seen from the front in FIG. 1, with a portion of the frame broken away;

FIG. 8 is a detail view, in vertical section along the line 8-8 of FIG. 3, showing certain driving connections incorporated in the machine;

FIG. 9 is a vertical sectional view taken along the line 99 of FIG. 3 showing certain other driving connections embodied in the machine;

FIG. 10 is a detail view taken from the bottom of FIG. 1, showing a portion of the work supporting member of the machine;

FIG. 11 is a view, partly in bottom plan and partly in horizontal section, showing certain parts illustrated in FIG. 10;

FIGS. 12A, B, C and D are views showing, from different positions, the form of the housing for the right hand plunger of the machine;

FIGS. 13A, B, C, D are similar views of the housing for the left hand plunger;

FIGS. 14A, B, C and D are views, taken from different positions, showing the righthand plunger of the machine;

FIGS. 15A, B, C and D are similar views of the left hand plunger of the machine;

FIG. 16 is a plan view of a portion of the machine showing the presser foot construction thereof in relation to the plungers and the needle;

FIG. 17 is a view of certain parts shown in FIG. 16, as seen along the line 1717 of the latter;

FIG. 18 is a detail view showing the position of the material being stitched in relation to the right hand plunger as the latter is at the top of its stroke; and

FIG. 19 is a similar view showing the various parts in the position in which the left hand plunger is at the top of its stroke.

The invention has been illustrated as applied to a machine of the type sold by Union Special Machine Com pany under the designation Style 150230. Its general nature is also disclosed in the patent to Roth et al. No. 3,288,094, granted Nov. 29, 1966, and some features are disclosed with certain modifications in the Fletcher-Forte pending applications Ser. No. 753,357 and Ser. No. 753,654, both of which were filed on Aug. 19, 1968. Reference may be made to the Roth et al. patent and to the above-mentioned applications for further details of the construction of the machine to which the present invention is shown as being applied.

Referring now to the drawings, the machine has a main frame provided with a base portion 7 (FIG. 1) adapted to be mounted on a suitable table or the like, and which has a vertical standard 8 rising upwardly therefrom, at the rear and right side thereof. From the top of the vertical standard there extends a horizontally disposed arm 8a from the left hand end of which there extends forwardly an arm 8b to a positionlust in front of the operator of the machine. A work supporting member 9 is rockably mounted on the forwardly extending portion of the base 7 of the frame. This work supporting member is rockably mounted on a fixed shaft 39 (FIG. 2) carried by upwardly extending portions of the base 7 of the frame. The machine is provided with a main drive shaft 10 journalled in suitable bushings and arranged to extend through the arm 8a of the frame. At its right end, as shown in FIG. 1, the shaft 10 extends outwardly from the frame and has secured thereto a hand wheel and pulley 11 adapted to receive a driving belt from a suitable power source, such as a conventional transmitter. Within the vertical standard 8 of the frame there is secured to the shaft 10 a toothed pulley 12 which cooperates with the upper end of a toothed belt 13, the lower end of which cooperates with a toothed pulley 14 mounted for free rotation about a fixed shaft 15 in the base of the frame of the machine. The toothed pulley 14 has twice as great a diameter as the pulley 12, so that pulley 14 will rotate only one revolution for two revolutions of the shaft 10.

The toothed pulley 14 has connected therewith, by a plurality of screws 16, an eccentric member 17. The latter is surrounded by a strap at the right end, FIG. 2, of a pitman 20. The left end of the latter is pivotally connected with a pin 21 extending horizontally from an element 22 which is secured to a rock shaft 23 journalled in bearing sleeves 24, 25, and 26 (FIG. 3) provided in the work supporting table 9. The rock shaft 23 is held against lateral movement by the element 22 and a collar 27, both of which are secured to the shaft 23. As will be seen from FIG. 3, the element 22 and collar 27 thrust against opposite ends of the bearing sleeve 24 to maintain the parts in the desired position.

In the course of operation of the machine the work table 9 is held stationary, so that the machine is what is known as a non-skip blindstitch machine. The only time that movement is imparted to the work supporting table is when the operator lowers it to permit the introduction or removal of work. However, it is also adjustable to a desired set position which will bring about a particular penetration of the work being stitched. Such penetration adjustment is effected by means of a regulating lever 28, FIGS. 1 and 2, which is rockably mounted intermediate its ends upon a fixed shaft 29. The latter has secured thereto a pair of collars 40 and 41 disposed at opposite sides of the hub-like portion of lever 28 which surrounds the shaft 29. This serves to maintain the various parts in the desired relation. At its upper end, the lever 28 has a forked portion 30 which straddles a cylindrical portion of element 31 that has a threaded end arranged to cooperate with internal threads provided on a stud 32, FIG. 2. At the outer end of this stud there is secured a knob 33 which is held in fixed relation to the stud by a set screw 34. The knob 33 carries markings adjacent its periphery which serve to indicate the extent of penetration for which the parts have been set.

The lower end of the lever 28 has a rounded face which engages the inner end of a rod 35 which is slidably mounted within bearing surfaces provided on the machine frame. A spring 36 having one end in engagement with a portion 3511 on the frame and its opposite end in engagement with a collar 37 adjustably secured to the rod 35 serves to urge the latter toward the right (FIG. 2) and into engagement with the lower end of the lever 28. The other end of rod 35 is engaged by an adjustable stop screw 38 carried by the apron portion 9a of the work table. A nut 38a serves to retain the stop screw 38 in its adjusted position.

It will be seen from the foregoing that the position of the work table 9 may be adjusted by the turning of the penetration knob 33 and thus determine the extent of penetration of the curved needle into the node of fabric which is pushed upwardly by the action of the node forming elements.

Referring now to FIGS. 8 and 9, it will be seen that an arm 42 having a clamping portion at one end is secured to the shaft 23 adjacent the left end of the latter as viewed in FIG. 1. As shown in FIG. 9 the arm 42 has its outer end portion connected by a pin 44 to a link 43. A snap ring 45 serves to retain the parts in assembled relation. At its lower end, the link 43 is connected by a pin 47 to an arm 46 which is clamped to a rock shaft 49. A snap ring 48 serves to retain the arm 46 connected with the pin 47. As shown in FIG. 1, the shaft 49 is journalled in bearings 50, 51 and 52 in three different areas. These bearings are carried by walls integral with portion 53 of the work support. Rock shaft 49 is parallel to the shaft 23 and is below and toward the rear of the latter as seen in FIGS. 8 and 9. Another arm 54 is clamped to the shaft 23 and this arm has pivotally connected therewith a link 55, by a pin 56 and a snap ring -57. The other end of the link '55 is connected to a pin 59 carried by an arm 58 which is clamped to a sleeve 61 surrounding the shaft 49. A snap ring 60 serves to retain the link 55 connected with the pin. The opposite end of the sleeve 61, as shown in FIG. 5, has clamped thereto an arm 62 which is connected with the housing, to be hereinafter described, which carries the right hand node forming plunger 65 for reciprocation of the latter. The left hand node forming plunger 64 is driven by an arm 63 which is clamped to the shaft 49 in the region adjacent the end of sleeve 61. The arrangement of the various parts mentioned is such that the shaft 49 and the sleeve 61 are held against any longitudinal movement.

As will be seen from FIGS. 1, 3 and 5 the plungers 64 and 65 are mounted for vertical movement in the enlarged portion 53 of the work table 9. Also it will be seen, from the connections shown in FIGS. 8 and 9 between the shaft 23 and the shaft 49 and sleeve 61, respectively, that the shaft 49 and sleeve 61 will be rocked in opposite directions from each other in the course of operation of the machine. Accordingly plungers 64 and 65 will be shifted longitudinally in opposite directions in relation to each other. For example, if the shaft 23 as shown in FIGS. 8 and 9 is rocked clockwise, the shaft 49 will also be rocked clockwise. However, the sleeve 61 will be rocked counterclockwise through the connections that have been described. It will be understood that during one revolution of the main drive shaft 10 the pitman will cause rocking 0f the shaft 23 in a clockwise direction, while on the next revolution of the main drive shaft 10 the pitman 20 will cause rocking of the shaft 23 in a counterclockwise direction. This of course results in causing lifting of plunger 64 during one revolution of the drive shaft and the lowering of plunger 65 during that revolution of the drive shaft, while on the next revolution of the drive shaft the plunger 64 will be lowered and the plunger 65 will be lifted.

An important feature of the present invention is the particular construction and arrangement of the two plungers. Considering plunger 64, it will be noted that its active portion 70 is disposed toward the right, FIG. 1, of the axis of the lower portion 68 of this element and the axis of its housing 74. On the other hand, the plunger 65 has its active or upper portion positioned toward the left of the axis of the lower portion of this plunger and toward the left side of its housing 88. A spring 85 within the lower portion 75 of the housing 74 has its lower end cooperating with the bottom 82 of this housing and its upper end cooperating with the under surface of the disclike portion 67 of the plunger. On the other hand the upper portion of plunger 65 is positioned toward the left side of its disc portion 101 which is urged upwardly by a spring 100 within the lower portion 89 of the housing of this unit. Referring to FIGS. 14 and 15 it will be seen that the portions of the two plungers 64 and 65 which are in engagement for relative sliding movement, i.e. the surfaces 71 and 73, are in vertical alignment with the peripheries of the disc-like portions 67 and 101 of the two plungers. This is a highly desirable arrangement since it insures proper reciprocation of each plunger along the desired path. It will be noted that the upper ends of the plungers are V-shaped, as shown at 72 in relation to plunger 64 and at 72a in relation to plunger 65.

Means are provided for varying the force normally applied by the springs 85 and 100 which serve to urge the respective plungers upwardly. As will be appreciated, the adjustment of this spring force is desirable in relation to the character of the work being dealt with. It should be adequate to insure the production of a desired node in the work when the housing of the node-forming plunger is shifted upwardly toward the work, in the manner to be explained. However, it should not be so great as to cause any injury to the workpieces. Such variation in the force of the spring is obtained by the turning of a knurled nut 84 which has internal screw threads which cooperate with threads provided on the lower end portion 69 of the plunger 64. The nut 84 is retained in its set position by the action of a spring element 86 that is secured by a screw 87 which has threaded engagement with the flange 76 of the housing 74. Similarly the force of the spring 100, which urges the plunger 65 upwardly, may be adjusted by the turning of a pair of nuts 99 upon the threaded lower end portion 98 of the plunger 65. Such adjustment is effected by the turning of the upper one of the pair of nuts 99 and it is retained in adjusted position by the locking action of the lower nut. The threaded end portion 98 of the plunger passes through a cup-shaped element which fits over the bottom of the housing 88.

The lower portions of the plunger housings, i.e. portion 75 of housing 74 and portion 89 of housing 88, are guided in their up and down movements by plates 102 and 103 (FIGS. 1, 10 and 11), these being secured to a horizontally disposed wall or partition 105 within the enlarged section 53 of the work table. Partition 105 has an opening 106 therethrough around the plungers and their housingsv Screws 104 are provided to secure the plates to said wall. The holes in the plates through which the screws 104 are passed are slightly larger than the shanks of these screws so as to enable accurate positioning of the plungers and their housings in relation to the work support.

The connections from the rock shaft 49 and the sleeve 61 to the housings 74 and 88, respectively, are illustrated in FIGS. 4, 5 and 6. Thus the connection from shaft 49 to the housing 74, for lifting and lowering the latter and its plunger 64, includes a rounded part 63a at the end of the arm 63 which cooperates with the top and bottom surfaces of a cutaway region 81 of the housing 74. Similarly, the connection from the sleeve 61 to the housing 88 involves the provision of a rounded part 620 (FIG. 6) extending laterally from the arm 62 and which cooperates with a cutaway region 94 of the housing 88. It will be understood of course that the plungers 64 and 65 will have their reciprocatory movements imparted to them by their connections with the respective housings described.

The upper portions of the two housings, namely por tion 77 of housing 74 and portion 90 of housing 88, are guided in a block which is preferably formed of two parts. One of these parts, identified as 107, guides the upper portion 90 of the right hand plunger housing 88 and has a downwardly disposed portion 108 (FIG. 7) which is secured by screws 109 to the front wall of the work table. Part 110 which guides the upper portion 77 of the left plunger housing is secured to the part 107 by a screw 111 (FIG. 3). As will be seen, the parts 107 and 110 are provided with vertical slots 112 and 113, respectively, for guiding the upper portions of the plunger housing. Those parts are further aligned with each other by means of a pin 114 (FIG. 3) which passes through and extends beyond the side of each part.

To insure the desired feeding of the work through the stitching region a special roller construction is provided, in lieu of the conventional feed platens. This involves a pair of rollers adapted to engage the under surface of the workpieces being stitched, and urge the same upwardly toward the stationary presser foot carried by the forwardly extending arm of the frame of the machine. This aspect of the invention involves a pair of pivoted bracket members 115 and 11-6 (FIGS. 1, 3, 4, 6 and 7) which are mounted for independent rocking movement on the frame of the machine. These members are rockable about the pin 114, which as stated above is carried by the two parts 107 and 110 secured to the work table. The rear end of the bracket 115 is provided with a pin 117, which extends toward the left of the bracket as these parts are shown in FIG. 3. Rotatably mounted on the pin 117 is a work engaging roller 118. In a similar manner the bracket 116 carries a pin 117a which extends toward the right from the bracket as shown in FIG. 3. Rotatably mounted on the pin 117a is a work engaging roller 118a. A spacer element or sleeve 119 surrounds the right end of the pin 114 and it has wrapped around it a spring 120, one end of which is bent to extend under the member 115 and the other end of which extends into an opening 121 provided in portion 53 of the work support. A similar construction is provided in relation to the bracket member 116, as shown in FIG. 3. In each case a washer element 122 is provided to retain the spacer and the spring referred to on the bracket member. A screw 123 threaded into the outer end of the pin 114 serves to retain the parts in assembled relation. At the forward end of the bracket 115 there is provided a small laterally extending shelf 124 which carries a vertically disposed stop screw 125 that is provided with a lock nut 126. The stop screw 125 cooperates with a pin 127, FIGS. 6 and 7, which is horizontally disposed in the extension 108 of the part 107. This serves to limit the upward movement of the feed roller 118 when the work table is lowered for insertion or removal of work. During the normal operation of the machine the spring 120 serves to urge the roller 118 under a suitable force against the lower surface of the work being advanced through the stitching zone. As shown in FIG. 6 the downward movement of the roller 118 is also limited by its cooperation with a shoulder 128, which is provided on the part 107 or is otherwise fixedly disposed in relation to the frame of the machine. Similarly the downward movement of the roller 118a is limited by a shoulder 129 provided On the part 110 or some other part fixed to the work support frame.

The presser foot assembly, against which the work is urged by the said rollers 118 and 118a, is illustrated in FIGS. 1, 4, and 16-19. As has been indicated, the presser foot remains in a stationary position, but it has various relatively movable parts associated therewith. A crown 130 is mounted on an eccentric portion 131a of a stud 131 having a head 132 adapted for turning, by a screw driver or the like, within an opening provided in an upwardly extending lug 133 provided on the presser foot, to bring about the desired cooperation between the plungers 64 and 65 and the work which is forced upwardly against the crown. The latter is adjusted in a direction toward or away from the path of the needle by the turning of the stud 131. After the stud has been set in its desired position it is locked by a set screw 134 which passes through the lug 133 and has its lower end in engagement with the stud 131. The end of the stud, as shown at the left in FIG. 16 extends into a bracket 135 which is adjustably secured by a screw 136 to the front face of presser foo-t member 137. The vertical position of the crown 130 may be varied to a certain extent by the turning of a thumb screw 138. The latter is held, in the position into which it has been set, by means of a set screw 139, the inner end of which engages a pellet 140, preferably formed of nylon or a similar plastic, and urges this against the threads of the thumb screw, thus creating a drag on the latter to resist accidentally turning. A spring 141 surrounding a portion of the stud 131 has one end cooperating with a projecting portion 130a of the crown 130. The opposite end of the spring cooperates with a portion of the lug presser foot member 137 FIG. 17. This arrangement is such that the crown is urged downwardly by the spring into its desired position in relation to the plungers 64 and 65. However, when one or the other or both of the plungers are forced upwardly against work to be stitched, the free end of the crown 130 may yield slightly against the force of the spring 141. When a heavy seam is being crossed in a stitching operation, and the crown is pushed upwardly, the thumb screw 138 stops this upward movement in the desired position determined by the setting of the thumb screw 138.

An edge guide 143 (FIG. 17) is adjustably secured to the forward face of the pressor foot. The edge guide is adjustable along the shoulder of a screw 144. Adjustment of the guide is brought about by means of a thumb screw 145 which has the guide attached to its free end by means of a snap ring 146. Thumb screw 145 has threaded engagement with an opening in lug 133 and is held in a desired position by a set screw 147 which serves to force a nylon pellet 147a (FIG. 1) against the threads of the thumb screw to retain it in set position.

In FIGS. 18 and 19 there is shown the cooperation of various parts of the node forming and work handling mechanism at different times during the operation of the machine. Thus in FIG. 18, the workpiece 149 is shown with a pair of folds 149a and 1491). At the time in an operation which is indicated in this view, the node former 65 is in its upward position in which it presents a node 153 in the path of the needle. The node is held against a depression 151 in the under side of the crown 130. Subsequently, when the parts reach the position shown in FIG. 19, the node former 65 will have been retracted and the node former 64 will have been raised to form a node 152 in the fabric and force this against the under surface of the crown 130, so that the needle at this time will pass through the node 152.

While a preferred embodiment of the invention has been shown and described in detail, it will be understood that various modifications may be made within the scope of the following claims.

What is claimed is:

1. A blindstitch sewing machine having a work supporting member which is retained in a fixed position during operation of the machine, means associated with said work supporting member adapted to form nodes in the work carried by said member, stitch forming means including a reciprocatory needle, means for reciprocating said needle, said node forming means comprising a pair of longitudinally extending elements having active portions of small cross-sectional area disposed closely adjacent to each other, each of said elements having a nonactive portion, said non-active portions of the two elements being spaced some distance apart, each of said elements having a housing at least partially enclosing said non-active portion thereof, springs surrounding said nonactive portions within said housings arranged to yielding- 1y retain said elements in a predetermined position in relation to their housings, and means for reciprocating the housings of said elements longitudinally to carry the active portions of said elements into and out of engagement with work carried by said work supporting member, said elements when shifted into engagement. with the work serving to place a portion of the work into the path of movement of the needle, the movement of one element being in the opposite direction from that of the other element in the course of their movements into and out of engagement with the work.

2. A blindstitch sewing machine as set forth in claim 1 in which the active portions of said elements have fiat surfaces which are in sliding engagement with each other.

3. A blindstitch sewing machine as set forth in claim 1 which has a main drive shaft, connections from said shaft for shifting said needle back and forth along an arcuate path, connections from said main drive shaft for rotating an eccentric member at half the angular speed of said main drive shaft, and connections from said eccentric member for reciprocating the housings of said node forming elements longitudinally, said last mentioned connections being arranged to shift one of said elements into engagement with the work and the other of said elements away from the work upon one revolution of said main drive shaft and for shifting each of said elements in the opposite directions upon the next revolution of said main drive shaft.

4. A blindstitch sewing machine as set forth in claim 1 in which said non-active portions of said elements have disc-like portions at their upper ends, the active portions of said elements extending upwardly from said disc-like portions eccentrically thereof.

5. A blindstitch sewing machine as set forth in claim 4 in which the active portions of said node forming elements are substantially cylindrical in form but have a part of the outer surface flattened, the flattened surfaces of the two elements being disposed in sliding engagement with each other.

6. In a blindstitch sewing machine as set forth in claim 1, a pair of rollers carried by said work supporting member and spring urged upwardly toward a fixed presser foot, said rollers assisting in the proper advance of the work through the stitching zone of the machine.

7. In a blindstitch sewing machine as set forth in claim 6, each of said rollers being carried by a separate member rockably mounted on said work supporting member.

8. In a blindstitch sewing machine as set forth in claim 7, one of said rollers being disposed in alinement with one of said node forming elements and the other of said rollers being disposed in alinement with the other of said node forming elements in the direction of feed of the work.

9. In a blindstitch sewing machine, mechanism for forming nodes in workpieces being advanced through the stitch-forming region of the machine which comprises a pair of vertically reciprocatory housings positioned adjacent each other and having openings in their adjacent sides, a node forming element vertically shiftable in each of said housings, springs within said housings for urging said node forming elements toward the work, the work engaging portions of said elements being disposed eccentrically of the axes of said housings and having parts of their outer surfaces in slidable engagement with each other.

10. In a blindstitch sewing machine as set forth in claim 9, a main rotary drive shaft, a rock shaft adjacent the stitch forming region of the machine, connections from said main drive shaft to said rock shaft for rocking the latter in opposite directions upon successive revolutions of said drive shaft, and connections from said rock shaft to said vertically reciprocatory housings for shifting one in the opposite direction from the other during each revolution of the drive shaft.

11. In a blindstitch sewing machine as set forth in claim 10, said connections from said rock shaft to said reciprocatory housings comprising a second rock shaft and a sleeve surrounding said second rock shaft, said last mentioned connections serving to rock said second rock shaft and said sleeve in opposite directions in relation to each other.

12. In a blindstitch sewing machine as set forth in claim 11, means connecting said second rock shaft with one of said housings and connecting said sleeve with the other of said housings.

13. In a blindstitch sewing machine as set forth in claim 9, means for adjusting the normal position of each node forming element in relation to its housing.

14. In a blindstitch sewing machine as set forth in claim 13, said adjusting means being adapted to enable independent adjustment of the node forming elements in relation to their housings and to the path of movement of the work pieces.

15. In a blindstitch sewing machine as set forth in claim 13, said adjusting means comprising a screw threaded portion on each of said node forming elements, and threaded members adjustably mounted on said screw threaded portions, each of said members being arranged to cooperate with a surface on its related housing.

References Cited UNITED STATES PATENTS 2,113,107 4/1938 Bowman 1l2178 2,189,433 2/1940 Mueller 112178 2,440,811 5/1948 Schifter 1l2178 2,658,464 11/1953 Greco 112178 H. HAMPTON HUNTER, Primary Examiner 

